A group of French students were allegedly chased through the streets by a gang of youths.
Police were called after their teachers turned up at the Harvester Restaurant in Lancing asking for help to find them.
The teachers told officers they believed the teenagers had run away after being harassed just before 10pm last night by the gang.
Several officers were called to conduct an area search around the restaurant in Grinstead Lane.
Most of the students, who were staying with host families nearby, were found within 40 minutes but it took officers longer to find a teenage boy.
A police spokesman said he returned to the home where he was staying by 10.45pm.
He said: "They were unharmed and there was no evidence of them being assaulted."
A spokesman for the Harvester confirmed the teachers had come in asking for help but refused to say more.
Operation Columbus was set up in Sussex four years ago to discourage incidents involving foreign students and local people.
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